This invention applies to hinges, more particularly to automotive door hinges, which facilitate motion of a closure panel relative to a fixed body structure, and simplify removal and reinstallation of the closure panel to and from the body structure during specific phases of the vehicle assembly operation.
Automotive door hinges are generally configured to include a door component that is rigidly attached to a closure panel and a body component that is rigidly attached to a body structure. This structural attachment of the components can be achieved by welding, riveting, bolting or similar mechanical fastening means. The simple rotary motion of the door component relative to the body component is normally achieved by a pivot pin and associated bearing surfaces. The pivot pin is configured to be rigidly attached to one of the hinge components while the other component freely rotates around the pivot pin via one or more bearing surfaces. It is normal practice to utilize two of these hinge assemblies, vertically offset with coaxially aligned pivot pins, to attach a closure panel to a body structure.
In many modem automotive vehicle assembly plants, the closure panel is removed from the body structure after the vehicle has been initially assembled and painted. This post-painting detachment of the closure panel is undertaken to facilitate ease of final assembly of the vehicle interior which includes installing large components such as the instrument panel, seats, carpet and headliner as well as simplifying the final assembly of the door hardware components such as the latch and window lift mechanism. An important aspect of the closure panel""s removal and reinstallation process is that it is normal practice to set the final door position during the vehicle""s initial assembly, prior to painting. In this way the gap margins and surface flushness, which are among the most important aspects of vehicle quality, are set during the initial structural framing and can be evaluated before and just after painting. This generally accepted approach requires that the method utilized to remove and reinstall the closure panel after painting, during the final assembly process, must facilitate exact replication of the original door position. There is a wide range of prior art that facilitates the removal and reinstallation of vehicle closure panels while maintaining the dimensional integrity of the original installation process.
One embodiment utilizes welding or bonding to permanently locate the hinge components"" floating, primary structural fasteners, which initially facilitated the adjustment of the closure panel relative to the body structure, subsequent to the acceptance of dimensional integrity. The closure panel can then be removed and reinstalled using the main hinge components"" primary structural fasteners with the entire hinge assembly either staying with the closure panel or the body structure. This methodology does not facilitate welding, riveting or bonding of either the door component to the closure panel or the body component to the body structure. Additionally, it requires that the paint integrity on the closure panel or the body structure be violated during removal of the closure panel.
A second prior art embodiment utilizes a two piece construction for either the door component or the body component of the hinge. This methodology allows the removal of the door from the vehicle without utilizing the primary structural fasteners. Either a two-piece door component or a two-piece body component is separated after painting the vehicle by removing one or more secondary threaded fasteners. It is common to utilize an aspect or portion of the additional component to fit over an extension of the hinge pin to help facilitate the reinstallation by providing a feature to temporarily hold the closure panel in approximate position before fitting the secondary threaded fasteners. This three-piece arrangement adds significant cost and complexity in comparison to a conventional two-element hinge configuration; also, the capability to dimensionally replicate the initial assembly location, during reinstallation of the closure panel, is somewhat limited.
A third prior art embodiment utilizes a cantilevered pivot pin which facilitates the door component being simply interleaved over the body component of the hinge. The door component incorporates a suitably sized pivot bushing that interacts with the vertical, body component-mounted, cantilevered pivot pin to assure that the positional tolerance of the assembled door and body components is closely held. A clip, nut or similar mechanical device retains the door component on the pivot pin and a horizontal bearing surface between the two components transfers the vertical loadings. This cantilevered pivot pin arrangement is referred to as single hung; it transmits all imparted bending moments directly to the pivot pin. This is in contrast to a double hung arrangement that utilizes a simply supported pivot pin that passes through two supports of the grounded hinge component and transfers all bending moment loadings in double shear as linear force couples. The single hung, interleaved door and body component hinge facilitates dimensionally accurate reinstallation of the closure panel but is structurally inferior to a double hung configuration.
Accordingly, it would be advantageous to create a hinge assembly in which the door component and body component can be simply separated after the closure panel has been properly fitted and structurally attached to the vehicle. Additionally, it would be a significant improvement over the existing art if the separation technique facilitated exact dimensional replication of the initial assembly location during reattachment of the two components while creating a fully structural, double hung pivot joint.
Accordingly, in an aspect of the invention, an automotive hinge adapted to facilitate removable attachment of a closure panel to a body structure comprises: a door component comprising upper and lower door component pivot arms adapted to be mounted to a vehicular closure panel; a body component comprising upper and lower body component pivot arms adapted to be mounted to a vehicular body structure; a common pivot axis around which the door component and body component are adapted to rotate; a cylindrical protrusion adapted to be coaxially aligned with the pivot axis and structurally attached to and extended above the upper pivot arm of the body component; such that the door component is adapted to interleave over the body component, dimensionally locating the closure panel and the body structure by means of an external cylindrical bearing surface on the cylindrical protrusion, and is adapted to be held in assembly by means of a pivot pin which is adapted to extend through both pivot arms of both hinge components to create a fully structural, double hung pivot joint.
In further aspects of the invention:
(a) the door component comprises an upper pivot bushing configured to fit tightly over the external cylindrical bearing surface of the cylindrical protrusion such that the positional tolerance of the assembled door and body components is closely held during reattachment of the closure panel after post-painting removal of the closure panel;
(b) the cylindrical protrusion comprises an internally threaded portion which interacts with an externally threaded portion of the pivot pin to provide a positive retention means for the pivot pin;
(c) the cylindrical protrusion comprises a machined component retained in the pivot arm of the body component by means of welding, bonding, material upsetting or similar mechanical fastening means;
(d) the cylindrical protrusion is formed out of the material of the pivot arm of the body component;
(e) the cylindrical protrusion comprises a smooth internal bore adapted to interact with a physical external feature on the pivot pin to provide a positive retention means for the pivot pin once it has been finally seated during reinstallation of the closure panel;
(f) the physical external feature on the pivot pin is a knurl, spline or other similar interface feature;
(g) the external cylindrical bearing surface on the cylindrical protrusion comprises a slight taper parallel to the pivot axis, to aid in lowering the separation forces required to separate the hinge components.